Some of you might recognize me, as I'm the girl who has been using Pivot since 2004 but still doesn't understand what's going on

So, being a total dummy, I've been trying to install some extensions (the Twitter/Facebook/GooglePlus buttons, to be exact) and I just can't see what I'm supposed to do.
I put the folders that I downloaded into the Extensions folder on my server, checked whether the PHP file was in the right location and... well... then what? Only one of them shows up in the Extensions tab in PivotX, so I ticked that... but not sure what's next. I tried adding the [[ twitterbutton ]] tag to the place in my templates where I'd like the buttons to go, but nothing shows up.
Now, I'm sure all of this is quite simple once you know what to do, but I can't find a simple explanation of the steps anywhere. Please help! Thank you so much!
Cheers from Brussels,
Anna Denise
www.annadenise.nl